Here's a look at some basic information about the upcoming developments:

What's going to happen on Oct. 1?

Beginning on Oct. 1, Americans looking for health coverage should be able to enroll in a private insurance plan through a state-based exchange -- online marketplaces where consumers can in theory comparison shop for health coverage, "just like you would for cell phone plans or plane tickets," as President Obama said in August.

The exchanges will be different in each state. In 16 states and Washington, D.C., state officials have decided to run their own exchanges, with their own regulations. The 34 remaining states will have their exchanges run by the federal government. Depending on the regulations in the state, the insurers that decide to join the exchange, and a variety of other factors, consumers could see a range in prices and options available.

States are also opening exchanges on which small business owners can purchase coverage for their employees. Not every state, however, is ready to launch their small business exchange.

Couldn't the government shut down on Oct. 1?

The government could partially shut down on Oct. 1 if Congress doesn't pass a spending bill to fund federal operations for at least a couple more months. It's coincidental that this date happens to fall on the same date that open enrollment on the exchanges begins.

Shutting down the government won't stop the exchanges from opening. Even if Congress fails to authorize discretionary spending by Oct. 1, the government has plenty of other sources of funding to draw from to keep the exchanges running. A large portion of the law is funded with mandatory spending -- which Congress is required by law to keep up unless the law is repealed -- as well as multi-year funds still available in the event of a government shutdown.

"It appears that substantial ACA implementation might continue during a lapse in annual appropriations that resulted in a temporary government shutdown," the nonpartisan Congressional Research Service said in a July report.

What happens if Congress "defunds" Obamacare?

Members of Congress on both sides of the aisle say they want to avoid shutting down the government, but some Republicans are insisting that any government funding bill include a provision to "defund" Obamacare.

However, for the very same reasons that Obamacare implementation would continue during a government shutdown, stripping Obamacare funding from a spending bill would have little practical impact. The only way to truly take back most of the money allocated for Obamacare would be to repeal the whole law.

If the Senate were to pass the House bill that "defunds" Obamacare (Democratic leaders in the Senate have vowed they won't, and President Obama has vowed to veto the bill), it would revoke some discretionary spending for the law. However, the administration could shift around resources in order to make up for the shortfall -- a move it's already taken to fund its Obamacare priorities.